Printing roller and means for making the same



Oct. 25, 1932. PRlEMER 1,884,214

PRINTING ROLLER AND MEANS FOR MAKING THE SAME Filed D60. 12, 1928 side view of the preferred form of the V grows.

Patented Oct. 25,1932

FRITZ IRIEMfER, OF ZSCHACHWITZ, NEAR DRESDEN, GERMANY PRINTING ROLLER AND MEANS FOR MAKING TIIE SAME Application filed December 12, 1928, Serial No. 825,635, and in Germany June 11, 1 928.

This invention relates to printing rollers for offset and lithographic printing andconsists essentially in covering the roller with a coating composed of Compressed leather dust,

co al and hardened oil.

The invention also relates to a process of applying the coating and consists in 171115 respect of mixing the ingredients in powdered form and feeding them in a thin stream to the place of contact between the rotating printing roller and a heated press roller, applying pressure to the coating by means of additional, solid press rollers, and retractlng the different press rollers from the printing roller in proportion as the coating grows.

The invention consists further in the provision of a machine wherein the rollers are mounted and operated for the purpose of carrying out the coating process.

The accompanying drawing represents a machine. H

For coating the printing rollers used in offset and lithographic printing, a mixture is used, according to the invention,-consisting of leather dust, copal andhardened oil. 7 The ingredients are mixed in powdered form, and the powder is fed in a thin stream between the roller while both are rotated, the rollers being retracted from each other as the coating The coating process is carried out in a machine which may be constructed as shown in the drawing. The machine frame 39 is mounted on a base 40 and provided with two horizontal parallel guideways 13 wherein two pairs of bearings 12 are adjustably mounted. A shaft 9 in one pair of bearingscarries the core 6 of the printing roller which core may be composed of wood or other suitable material. Another pair of bearings holds a shaft 10 which carries a hollow press roller 7 the surface 8 of which is heated by gas supplied through a pipe 11. The roller 7 receives motion from a belt '17'thro'ugh the medium of a pulley 18, and the motion is transmitted to the printing roller at-a considerably increased speed through the medium of gear wheels 19,20, 21 and 22. The

printing roller and the heated press coating materialpowdered and well mixed,

is placed in a hopper 2 which is mounted on legs 1 above the rollers and fitted with a lid 3. A narrow discharge slit 4 at a downwardly projecting part of the hopper, 1:; is adapted to feed the powdered mixture in a thin stream into the place of contact between the rollers 6 and 7. The powder is melted by the press roller and adheres to the printing roller under the pressure so as to C5 form a coating 16 thereon, The pressure is applied through the medium of the bearings 12 which for this purpose are controlled by screw-spindles l4 fitted with lock-nuts 15. The rollers are" retracted from each other by C5 means of the screw-spindles in proportion as the coating grows. Indexes 42 on the bearings indicate with reference to graduated scales on the guideways the temporary thickness of the coating. Material which does not adhere to the printing roller falls on to a chute 43 and is delivered by the latter into a receptacle 41.

-A series of additional, solid press rollers 26 are arranged under the printing roller. These press rollers are mounted by means of shafts 27 in bearings which are adjustable in guideways 28 by means of screw-spindles 29 fitted with lock-nuts 30. Motion is transmitted to. the additional press rollers from the gear wheel 22 through idle gears 23 and 24 t e latter of which mesh with wheels 25 mounted on the shafts 27.

In order to roughen the surface of the finished coating, a rotary or like brush 34 is provided which is also mounted by means of a shaft 33 in bearings controlled within guideways 36 by means of screw-spindles 38 fitted with lock-nuts 37. The brush roller is rotated by means of across-belt 35 which runs on a pulley 32 on the shaft 33 and a pulley 31 on the adjacent shaft 27. Y

The printing roller may be enclosed in a casing The roller surface thus produced will be highly elastic, water-repellant and greaseattracting.

I claim:

1. A process of covering a printing roller with a coating of leather dust, copal and hardened oil, consisting in mixing the ingredients of the coating in powdered form, feeding the powder in a thin stream on to the rotating printing roller,-heat' the powder on the roller, and pressin e stream of powder continuously on to t e roller surface. 2. A machine for coating printing rollers I comprising a frame, horizontal guideways in said frame, a hollow press roller, bearings for said press roller mounted in the guideway, bearings in said fuideways for the printing roller, means or controlling the positions of the bearings so as to mamtain the printing and press rollers in contact with each other, a hopper having a-narrow discharge slit adapted to feed powdered coatin material in a thin stream to the contact mts between the rollers, means for im artmg motion to the roller and means for cating the press roller.

3. The device claimed in claiin 2 in combination with additional, solid press rollers arranged under the printing roller, and means for a justing said additional pres rollers relative to the printing roller.

4. The device claimed in claim 2 in combination with a rotary wire brush for rou hing the surface of the coated printing r0 er.

FRITZ PRIEMER. 

